Description: Preliminary studies indicated that 2,2,4,4,5,5- HCB significantly inhibited 3,3,4,4,5-pentaCB-mediated teratogenicity and future collaborative studies will further characterize the nature of these non-additive interactions. The developmental toxicity of chlorinated phenols, which are major components of wood-preserving wastes, was investigated using a series of developmental toxicity assays, including in vivo segment II studies in rats, hydra assay, HEPM, and whole embryo culture. The effects of these compounds in primary cell culture bioassays will be carried out in future studies. Field- practical methods for the detection (minicolumn assays) and detoxification (clay minerals) of mycotoxins have been developed and patented by Dr. Phillips. The basic technologies have been licensed and commercial products are currently being used worldwide. The proposed research in this program project will further enhance this diagnostic assay for chlorophenols (CPs) and also utilize clay-based technology for the degradation of CPs and other halogenated aromatic hydrocarbons (HAHs) associated with oily and wood-preserving wastes.